Drys shaver having a single spring means as a drive element and to retain the inner cutter in the shaver head when said head is removed



Aug. 13, 1968 R. NEUMANN ET AL 3,396,463

DRY SHAVER HAVING A SINGLE SPRING MEANS AS A DRIVE ELEMENT AND TO RETAIN THE INNER CUTTER IN THE SHAVER HEAD WHEN SAID HEAD IS REMOVED Filed June 13, 1966 1r+| FIG.1

FIG. 2

7 FIG. 9

I mvemoRs ROLAND NEUMANN ei 0| United States Patent DRY SHAVER HAVING A SINGLE SPRING MEANS AS A DRIVE ELEMENT AND TO RETAIN THE INNER CUTTER IN THE SHAVER HEAD WHEN SAID HEAD IS REMOVED Roland Neumann, Rappelsdorf, Kries Suhl, Thuringia, Horst lViinschmann, Suhl, Thuringia, and Paul Ehrhardt, Schmiedefeld-Rennsteig, Thuringia, Germany, assignors to VEB Elektrogeratewerk Suhl, Suhl, Thuringia, Germany Filed June 13, 1966, Ser. No. 557,294 6 Claims. (Cl. 3043.92)

ABSTRACT OF THE DISCLOSURE In a removable shaver head having a base plate, a stationary outer cutter, a movable inner cutter, a W- shaped leaf spring as a drive element of the inner cutter, and a retaining plate fixed to the base plate, said spring being coupled to the inner cutter by means of slide joints on its ends, and being provided with downwardly directed lugs which due to the spring action are retained by the retaining plate when said head is removed.

This invention relates in general to a shaver head for a dry shaver, and in particular to a leaf spring provided on the inner cutter of the dry shaver.

Shaving heads for dry shaving devices are known, wherein a leaf spring is fixedly connected at one end thereof to the lower knife and is slidable along the inner cutter at its other end. When mounting the shaving head on the dry shaving device, a pin engages a centrally disposed bend on the leaf spring and presses the leaf spring together with the inner cutter against the outer cutter, thus achieving a continuous constant pressure during the reciprocating movement of the inner cutter. To prevent a dropping of the inner cutter from the shaving head during removal of the shaving head, that is, when the engaging pin is disconnected from the bend of the leaf spring, shoulders are provided on the leaf spring which automatically engage slots on a support which are connected with the outer cutter, so as to automatically effect a central position of the inner cutter against the outer cutter. The mounting of the leaf spring on the inner cutter is performed so that the leaf spring is deflected with each end disposed angularly against the inner cutter, whereby one end of the leaf spring is mounted in stationary position in a slot of the inner cutter, While the other end, a T- shaped end, is mounted slidably in a keyhole slot of the inner cutter.

However, shaving heads of this type have certain shortcomings. It has been noted that the angularly deflected end of the spring which is slidably mounted in the keyhole slot of the inner cutter is subject to heavy wear on the sides thereof, and after a certain period of operating, results in breakage, so that a continuous constant pressure of the inner cutter against the outer cutter is no longer possible. Thereupon, since the inner cutter is not in contact with the leaf spring, on the side where the breakage occurs, the cutting capacity of the device is reduced and a loud noise results. The same wear phenomenon, but only to a reduced extent, is present on the end of the leaf spring which is fixedly mounted on the inner cutter, which may also result in a breakage. Furthermore, leaf springs which have relatively weak deflected ends, particularly the receiving ends thereof, are subject to an increased waste, during the production process. Another shortcoming is that the engaging face of the leaf spring against the inner cutter is rather small, so that it is subject to an increased wear, after a longer period of operation of the device and satisfactory contact pressure of the inner cutter against the outer cutter is no longer possible.

It is, therefore, an object of the invention to remove these shortcomings which are caused by using the abovementioned spring leaf.

It is a further object of the invention to provide a shaving head wherein a continuous contact pressure of the inner cutter against the outer cutter is made possible by means of a leaf spring, during the operating performance of the device, and wherein the leaf spring is shaped in such a manner that the danger of breakage and wear are substantially avoided.

These objects are achieved in accordance with the invention in that the W-shaped dn've leaf spring comprises two acute-angled lugs which are deflected toward an opening of a retainer plate which is fixedly arranged in the shaver head. When the shaving head is removed and the driving lever is disconnected from the central bend of the leaf spring, the lugs engage automatically an opening of the retaining plate, such forming a safety device to prevent dropping of the inner cutter from the shaving head. Furthermore, a centering during the remounting of the shaving head onto the housing of the shaving device and onto the engaging pin is made possible due to the angular guiding faces which are disposed on both sides of the bend. The leaf spring is provided with rounded portions at its ends which are in contact with the inner cutter. One end of the leaf spring which is provided with an opening engages an acute angled tongue of the lower knife in such a Way that a minimum backlash is provided. The other end of the leaf spring is provided with a keyhole opening in known manner, and engages slidingly the rectangularly deflected T-shaped tongue on the other end of the inner cutter. The leaf spring is reduced in thickness, in the central area between said acute-angled lugs.

The technical and economical effects of the invention are the employment of a leaf spring which substantially avoids the danger of breakage and wherein only minor waste occurs during the making of the leaf spring.

For a better understanding of the invention, its operating advantages and the specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter, in which:

FIG. 1 is a partial front section of the dry shaver showing the inventive leaf spring in a biased operative position;

FIG. 2 shows a cross section of the dry shaver taken on the line IIII of FIG. 1;

FIG. 3 is a front sectional view of the shaving head alone with the driving rocking lever removed, and with the leaf spring in a locked position;

FIG. 4 is a longitudinal section of the inner cutter alone;

FIG. 5 is -a top plan view of an inner cutter alone;

FIG. 6 is a broken bottom plan view of the inner cutter;

FIG. 7 is a side view of a leaf spring alone;

FIG. 8 is a top view of a leaf spring; and

FIG. 9 is a side View of a oross-section of the inner cutter on an enlarged scale.

With reference to the drawings, and in particular to FIGS. 1 and 2, it can be seen that shaving head 2 consists of a base plate 5 upon which there is fixedely mounted a stationary outer cutter 3 and a retaining plate 4 having an opening 19 at its center. A movable inner cutter 7 operatively engages said outer cutter 3. Inner cutter 7 is supported on its ends by a W-shaped leaf spring 8, having a converging central portion for receiving a driving rocking lever 21, and symmetrically arranged upwardly inclined shoulders which are at their lower ends provided with lugs 12. The rocking lever 21 is situated in a shaver housing 1 through which it projects upwardly to drive the shaver head 2. The shaver head 2 is removably secured to said housing by means of lateral retaining grips 6 on base plate and retaining springs 9 on said housing. For fastening leaf spring 8 onto inner cutter 7, two tongues 10 and 11 are provided on the lower portion of inner cutter 7, disposed at the respective ends thereof. See FIG. 4. One of these tongues 10 is deilected in an acute angle toward the center of the inner cutter, and the other tongue 11 extends at a right angle to the inner cutter. With reference to FIG. 7, it can be seen that leaf spring 8 is shaped in such a way that acute angled tongues 12 are provided on the lower ends of inclined spring shoulders near to the junction with guide faces 13. At opposite ends of leaf spring 8, slots 14 and 15 are provided. One slot 14 is right angularly shaped, while the other slot 15 at the opposite end of the spring is a keyhole-shaped opening, as can best be seen in FIG. 8. Leaf spring 8 is further provided with a bend 16 in the center thereof and with rounded portions 17 at its ends, bent in direction opposite to that of the bend 16. Leaf spring 8 is mounted on inner cutter 7 by positioning right angular slot 14 of the spring over acute angled tongue 10 of inner cutter 7, which provides a slight tolerance. Then the keyhole-shaped opening 15 is slidab ly positioned over the right angularly extending tongue 11 of inner cutter 7.

Then the leaf spring 8 is mounted in the shaving head 2 by inserting the bend 16 into a central opening 18 of the inner cutter 7. See FIG. 1. Rounded portions 17 act to reduce the friction during the operating performance of the device as much as possible and to reduce wear, due to the relatively large engaging faces.

The positioning of inner cutter 7 against outer cutter 3 is effected and maintained by exertion of a slight contact pressure by leaf spring 8 against inner cutter 7, so that lugs 12 move freely through a central opening 19 in retaining plate 4 and above the retaining plate.

As the shaving head 2 is removed from the dry shaving device, the leaf spring 8 is no longer pressed against the inner cutter 7 by the driving rocking lever 21. The

inclined guide faces 13 then tend to approach a flat position and to spread the angle lugs, which then contact the inner face in the opening 19 of the retaining plate 4. Since the leaf spring 8 remains in contact with the inner cutter 7, it prevents the inner cutter from dropping out of the head.

When mounting shaving head 2 onto spring leaf 8 an automatic centering of engaging lever 21 is assured due to the inclined guiding faces 13 of leaf spring 8. For achieving a soft spring action, leaf spring 8 is thinned in the area between the acute angle lugs 12.

What is claimed is:

1. A dry shaver having a housing, an elongated drive element located in said housing and projecting therethrough, a shaver head attached on said housing in the region against said projecting drive element, said shaver head comprising a base plate removably secured to said housing by retaining means, a stationary outer cutter fixed to said base plate, a movable inner cutter operative- =1y engaging said outer cutter, a W-shaped leaf spring means having the converging central portion adapted for guiding and receiving said drive element, and the upwardly inclined shoulders adapted for supporting said inner cutter, slide joint means arranged on free support ends of said shoulders and on corresponding ends of said inner cutter for providing a firm bayonet joint between said spring means and inner cutter when the spring means is biased by said drive element, a plurality of downwardly directed lugs integral with lower ends of said shoulders and lifted therewith when the spring means is biased by the drive element, a lug retaining means fixed to said base plate beneath said plurality of lugs to retain the latter when the drive element is removed and the leaf spring means automatically lowered to its non-biased position.

2. The dry shaver according to claim 1 wherein said slide catch means includes a downwardly directed tongue on each end of said inner cutter and a fitted slot on each end of said leaf spring.

3. The dry shaver according to claim 2 wherein one of said tongues is T-shaped and the corresponding slot has a key-hole shaped cross-section for providing a bayonet joint, whereas the opposite tongue and corresponding slot are adapted for providing a hinge joint without a backlash.

4. The dry shaver according to claim 1 wherein said leaf spring means is reduced in thickness in the area between the lugs to attain an improved spring action.

5. The dry shaver according to claim 1 wherein the free ends of said leaf spring are rounded to reduce wear of the leaf spring means during operation.

6. The dry shaver according to claim 1 wherein said lug retaining means is :a plate parallel with said base plate and provided with a central opening in the region beneath said plurality of lugs to receive the latter when said leaf spring means returns to its non-biased position.

References Cited UNITED STATES PATENTS 2,325,267 7/ 1943 Murphy 3043.92 2,360,679 10/1944 Holsdlaw 3043.92 3,172,201 3/1965 Messinger et al 3043.92 3,191,299 6/1965 Locke 30-4392 3,201,866 8/1965 Parrello 30 4392 MYRON C. KRUSE, Primary Examiner. 

